Method and apparatus for securing tiles to curtain wall mullions

ABSTRACT

The present invention relates to a method and apparatus for securing porcelain and ceramic tiles to curtain wall mullions comprising the use of structural panels made of light-weight but rigid materials, such as aluminum. The tiles are preferably secured to the panels using structural silicone, and secured to the frame using components such as tile retainers, stops, gaskets and sealants. The frame is preferably made of snap-together members and supported by building structures to withstand lateral loads, such as caused by heavy wind pressure and flying debris.

BACKGROUND OF THE INVENTION

[0001] Buildings constructed in certain areas of the country, such as inthe Southeastern states, are often subjected to extreme weatherconditions, including hurricanes and gale force winds. Building codes inthese areas are often strict to ensure that the buildings that areconstructed can withstand these conditions. For example, many buildingcodes require exterior walls to be constructed in a manner that resistswind blown debris and high wind pressures, such as by requiring thatthey be able to resist lateral loads of up to 75 pounds per square feet.In areas where the threat of hurricane damage is especially high, testsmust also be conducted requiring walls to resist the impact of a two byfour inch piece of wood, nine feet long and weighing nine pounds,striking the exterior wall (like a missile) at 35 miles per hour or 50feet per second.

[0002] Porcelain and ceramic tiles are sometimes used on exterior wallsbecause of their aesthetic value and long lasting durability. In areaswhere the threat of hurricane damage exists, however, the ability to usesuch tiles is limited because of the difficulty of making the wallsstrong enough to meet the strict building code requirements. Although itis possible to use such materials, the tiles must be thick and strongenough to satisfy the requirements, thereby increasing constructioncosts. Not only must larger and more expensive tiles be used, but theadditional costs associated with having to transport, lift and installlarger and heavier pieces can be burdensome. Although technologicaladvancements have made it possible to manufacture porcelain and ceramictiles that are stronger in tensile strength than in the past, thedifficulty in meeting the strict requirements still exists forapplications in many areas of the country.

[0003] What is needed, therefore, is a method and apparatus for securingporcelain and ceramic tiles to curtain wall mullions that enhances thestrength of the walls without necessarily increasing the cost andweight, so that the strict building code requirements that exist inareas where the threat of hurricane damage is high can be satisfied.

SUMMARY OF THE INVENTION

[0004] The present invention relates to an improved method and apparatusfor securing porcelain and ceramic tiles to curtain wall mullions tosatisfy the strict building code requirements that exist in areas wherethe threat of hurricane damage is high. In existing curtain wallstructures using mullions, there is typically a support frame made ofhorizontal and vertical framing members, such as made of metal oraluminum, which are spaced a predetermined distance apart from oneanother, i.e., to form a structural frame on which the exterior tilescan be applied. The frame is typically sized so that it can fit betweenfloors, extending from one floor to the next floor, and in numberssufficient to extend around the exterior periphery of the building.Where the upper floor is the top of the building, the frame can also becantilevered above the upper floor. In a typical curtain wallapplication, the spacing between the mullions is anywhere between 2-3feet.

[0005] The curtain wall of the present invention is preferablyconstructed using prefabricated framing members such as those that canbe snapped into place using a minimum number of fasteners. For example,each of the vertical mullions can be constructed from male and femalemullion halves which snap together along their edges to form asubstantially rectangular tube-like member. Likewise, the horizontalmullions can come in two pieces, which allows fasteners to be installedfrom inside. That is, an opening can be provided along the mullionmember, and provided with a removable cover plate, so that fasteners,such as nuts and bolts, can connect the member to other structuralmembers from the inside. On the other hand, the present invention can beconstructed using virtually any type of framing members sufficient tosupport the tiles thereon in the manner discussed.

[0006] Additional members, such as tile retainers, retaining covers, andtile stops, may also be used to facilitate the attachment of the tilesto the frame. In this respect, a tile retainer is preferably providedalong the upper and side edges of the tiles along the upper and sideportions of the frame. A retaining cover is then used to hide the tileretainer, which can be secured to the frame using fasteners such as nutsand bolts. Tile stops can also be provided along the lower tile edges tosupport the weight of each tile. These stops are preferably secured tothe mullions and extend outwardly so that the tiles can rest thereon.Gaskets and other sealants can be used around the periphery of the tilesto secure and seal the tiles to the frame.

[0007] In one aspect of the present invention, structural panel inserts,such as made of light weight aluminum, are provided within the spacesbetween the mullions. Square or rectangular panels can be sized andfitted into the spaces formed by the mullions and secured usingconventional fasteners such as nuts and bolts. The structural panels arepreferably thin but strong enough to provide reinforcement againstlateral loads and impact from debris. The panels preferably have anglededges extending a predetermined distance rearwardly from the front ofthe panels to provide rigidity and support. The angled edges preferablyextend around the perimeter of each panel and provide support againstlateral loads.

[0008] Another aspect of the present invention is that the porcelain andceramic tiles that are used are relatively thin in comparison to thetiles that have been used in the past for such curtain wallapplications. In the preferred embodiment, the tiles can be as thin asabout ⅜ inch, thereby making each tile relatively light-weight and easyto handle. Each tile is also cut and sized to fit over the spaces formedby the horizontal and vertical mullions, and extended about half-wayover each of the mullions so that proper attachment and support can beprovided by the frame.

[0009] Another feature of the present invention is that structuralsilicone is preferably used as a means of securing the tiles to theframe and/or the structural panels. Structural silicone has adhesiveproperties which enable the tiles to be glued to the frame, and haselastic properties which help to cushion the tiles in relation to theframe while providing spacing therebetween. The structural silicone canbe applied directly to the structural panels, as well as along the edgesof the mullions, to properly seal and secure the tiles to the frame.Additional gaskets can also be applied along the edges of the tiles andframe to ensure that the walls are wind and moisture resistant.

[0010] In the preferred embodiment, the tiles are fully secured to theframe without any evidence of any mechanical or structural fastenersfrom the exterior That is, the structural silicone is preferably placedbehind the tiles so that they are hidden from view, and the gaskets andother sealants are preferably placed behind and/or along the edges ofthe tiles so that they are substantially hidden. The retainingcomponents are also preferably extended around the periphery of the wallso that they are visually integrated with the building structure.Retainer covers can also be used to hide the retainer components. Thesefeatures enhance the aesthetic appearance of the curtain wall of thepresent invention, thereby maximizing the benefits of the porcelain andceramic tiles that are used, and the designs that are provided thereon.

[0011] The use of the structural panels behind the tiles, in combinationwith the structural silicone, enables the curtain wall structure of thepresent invention to provide additional strength and resistance againstlateral loads due to wind and impacts due to wind blown debris. This isparticularly important in areas where the threat of hurricane damage ishigh, such as in the Southeastern areas of the U.S. The use of therelatively thin tiles and the relatively light-weight panels allows forthe construction of the walls to be rapid and cost-effective. Theability to reduce the thickness of the tiles allows the curtain wall ofthe present invention to be manufactured at a lower cost than inprevious designs.

BRIEF DESCRIPTION OF DRAWINGS

[0012]FIG. 1 is a typical front elevation view of the curtain wallmullion frame of the present invention with horizontal and verticalmullions;

[0013]FIG. 2 is a side cross-section view of the curtain wall of thepresent invention showing various details;

[0014]FIG. 3 is a horizontal section view from above of the curtain wallof the present invention showing various details;

[0015]FIG. 4 is a typical side cross-section detail view of a joint nearthe upper edge of the curtain wall of the present invention;

[0016]FIG. 5 is a side cross-section view of a cantilevered embodimentof the curtain wall of the present invention;

[0017]FIG. 6 is a typical side cross-section detail view of a connectionbetween the tile and frame along one of the joints of the curtain wallof the present invention;

[0018]FIG. 7 is a horizontal section detail view from above of aconnection between the wall and horizontal support member;

[0019]FIGS. 8a through 8 h are cross-section views of the variousmembers that are used to construct the curtain wall of the presentinvention; and

[0020]FIG. 9 is a an exploded perspective view of the connection betweenthe horizontal and vertical mullions used in the curtain wall of thepresent invention.

DETAILED DESCRIPTION OF THE INVENTION

[0021]FIG. 1 represents an elevation view of a typical mullion frame 1having horizontal 3 and vertical 5 members that are spaced apart apredetermined distance, x and y, respectively. The horizontal andvertical members 3 and 5 are preferably made of structurally rigid butlight-weight materials, such as aluminum, and are preferably connectedtogether by conventional means to form a substantially rigid frame 1.Each frame 1 is intended to span the vertical distance between twosections of the building, such as between two floors, wherein the bottomof the frame can be connected to one floor, and the upper part of theframe can be connected to the floor above it. When the frame 1 is usedalong the top of a structure, the top section 7 of the frame can becantilevered above the top floor, as shown in FIG. 5. The maximumdistance between each mullion, x and y, in both horizontal and verticaldirections, is preferably about 3 feet, although spans which provide theappropriate structural support can be provided where appropriate.

[0022] Each of the horizontal 3 and vertical 5 members are, in thepreferred embodiment, made of extruded aluminum or other metal, andcomprise multiple pieces which can be snapped together for ease ofconstruction. These members can, however, be made in any conventionalmanner without departing from the present invention. For example, thehorizontal members 3 are preferably made of a rectangular tube portion 9with an opening 10 therein covered by a removable cover plate 11, whichcan be snapped into the tube portion 9 to seal the opening 10, as shownin FIG. 2. Being able to remove the cover plate 11 from the tube portion9 enables construction workers to access the interior of the tubeportion 9 so that fasteners 13 or 16, such as nuts and bolts, can betightened from inside. A cross section detail view of the tube portion 9is shown in FIG. 8a, and the snap-in cover plate 11 is shown in FIG. 8d.

[0023] In FIG. 3, the preferred vertical members 5 of the frame 1 areshown in cross-section. Each vertical member 5 is preferably comprisedof two halves, one a male mullion portion 35, as shown in FIG. 8g, andthe other half a female mullion portion 37, as shown in FIG. 8h. Thesehalves are preferably adapted so that they can be snapped together, asshown in FIG. 3, wherein the two halves 35, 37 can form a singletube-like member 5. Each of these vertical members 5 are adapted toextend substantially the height of each frame. They can also be extendedabove the upper floor to form a cantilever 7, as shown in FIG. 5. One ormore nuts and bolts 60 are preferably provided at about midspan on eachvertical mullion, as shown in FIGS. 3 and 7, to help keep the two halvestogether and prevent buckling.

[0024] To form the frame 1, the horizontal mullions 3 are secured to thevertical mullions 5 at predetermined locations forming a grid pattern asshown in FIG. 1. To make the connections, frame assembly screws 39, asshown in FIG. 9, can be inserted through holes 40 drilled in thevertical mullions 5 and extended into screw receiving portions 41 on thehorizontal mullions 3. The ability of the vertical muillion halves 35and 37, and horizontal mullion members 9 and 11, to be separated,enables workers to access the interior spaces inside the mullions toinstall and tighten the fasteners as discussed.

[0025] For each frame 1, the maximum spacing x between the horizontalmullion members 3 is preferably about three feet, and the maximumspacing y between the vertical mullions members 5 is also preferablyabout three feet. Using the maximum spacing, the maximum preferreddimensions of the spaces between the horizontal 3 and vertical 5mullions is about three feet by three feet, or constitutes an area ofabout nine square feet. In existing curtain wall structures, thesespaces are required to be spanned by the exterior surface, such as bythe tiles themselves.

[0026] As shown in FIGS. 2 through 7, one of the improvements providedby the present invention is the use of structural panels 43, that arepreferably provided within the spaces between the mullions 3 and 5.These panels 43 provide structural strength, rigidity and support forthe porcelain and/or ceramic tiles 23 that are to be positioned on thefront. The structural panels 43 are preferably made of a strong, butlight-weight material, such as aluminum, which can be made relativelythin, but which can also provide structural strength and rigidity to theframe 1. The structural panels 43 preferably have an angled edge 45, asshown in FIGS. 2 through 7, that extends around the perimeter of thepanels. The angled edge 45 is preferably extended a predetermineddistance rearward from the front surface 44 of the panels 43, i.e., in adirection normal to the panels, to provide support and reinforcementagainst lateral loads. The panels 43 themselves are preferablyrelatively thin, i.e., as little as ⅛ inch in thickness, in thepreferred embodment.

[0027] The structural panels 43 are preferably secured to the horizontal3 and vertical 5 mullions with bolts or screws or other fasteners 47, asshown in FIGS. 2 through 7, in a manner sufficient to support the panelsthereto, such as every 12 inches on center. The fasteners 47 can beextended through holes drilled in the angled edges 45 and into themullions 3 and 5, so that the panels 43 are supported by the edges 45.

[0028] As shown in FIG. 2, the tiles 23 are preferably secured to thefront of the frame 1 in the manner discussed. The preferred method ofsecuring the tiles 23 to members of the frame 1, including thestructural panels 43 and mullions 3 and 5, is by using structuralsilicone 24, such as GE 4000 silicone manufactured by General Electric.Preferably the silicone 24 is applied in a ½ inch diameter bead, atabout 8 inches on center, along the front surface of the structuralpanels 43. The tiles 23 can be positioned on the panels 43 and adheredthereto. The silicone 24 provides a means of adhering the tiles 23 tothe panels 43, but also cushions the lateral loads that may be appliedto the wall. An interior glazing gasket 51, as well as the silicone 24,can be provided around the perimeter of the tiles 23 to seal the spacesbetween the tiles 23 and mullions 3 and 5, and to provide supporttherefore. Between adjacent tiles 23, additional glazing compounds 52can be used to seal the space or gap therebetween.

[0029] Along the upper and side edges of the frame 1, the tiles 23 arepreferably held by retainers 17 extending from the mullions 3 and 5. Inthis respect, the front portion of each mullion 3 and 5 preferably hassnap fittings upon which the tile retainers 17 can be secured. The tileretainer 17 is preferably used only along the upper and side edges ofthe curtain wall to retain and seal the perimeter edges of the tiles 23as shown. In the horizontal members 3, the tile retainer 17 ispreferably configured to snap into the front of the tube portion 9 alongthe top edge thereof, and has a retaining portion 21 which can be usedto retain the upper edges of the tiles 23 in place. A snap-in filler 67is provided that can be attached to the lower front portion of themullions 3, to fill the space between the mullions 3 and tiles 23.

[0030] In the vertical members 5, the tile retainer 17 is preferablyconfigured to snap into the female half 37 along the side edges thereof,and has a retaining portion 21 which can be used to retain the sideedges of the tiles 23 in place in a similar manner. The snap-in fillers67 can be attached to the front of the mullions 5, to fill the spacesbetween the mullions 5 and tiles 23.

[0031] The tile retainer 17 is preferably secured to the mullions 3 and5 by a fastener 25, such as a nut and bolt, extending through theretainer 17, and the front of the mullions 3 and 5. A retainer cover 19is preferably adapted to be snap fitted onto the tile retainer 17 tocover the fastener 25 and provide the desired aesthetic appearance. Anexterior glazing gasket 53 can be provided along the outer edges of thetiles between the tile retainer 21 and tiles 23, as shown in FIGS. 2through 5.

[0032] Along the lower edges of the tiles 23, and along the lower edgeof the frame 1, there is preferably a tile stop 59, as shown in FIGS. 2and 6, extending from the horizontal mullions 3. The stop 59 essentiallysnaps into and extends outward from the mullions 3 and provides a ledgeupon which the tiles 23 can be positioned and supported. The stops 59and mullions 3 are preferably adapted so that the stops 59 can snap intothe front of the mullions 3 as shown in FIG. 6. Additional interiorgaskets 51 can be used to fill and seal the spaces between the stops 59and tiles 23. The gaskets 51 can provide a cushion effect for the tiles23. Additional structural silicone 24 can also be used to seal thejoints.

[0033] As shown in FIG. 2, the structural panels 43 are positioned suchthat they provide structural support laterally for the tiles 23.Preferably, the front surface 44 of the structural panels 43 extendssubstantially flush with the back of the tiles. In this respect, thefront of the panels 43 is preferably flush with the snap-in fillers 67,so that the tiles 23 can be secured to both the structural panels 43 andthe framing members 3 and 5 along substantially the same plane. Eachtile 23 is preferably sized to extend beyond the outer edges of thestructural panels 43 and to overlap the front of the mullions 3 and 5,so that there is an adequate margin for the tiles 23 to be secured tothe mullions 3 and 5. Because each tile 23 is supported by thestructural panels 43 from behind, and structural silicone 24 is providedat regular intervals between the tiles 23 and panels 43, and interiorgaskets 51 are used to seal the spaces between the tiles 23 and mullions3 and 5, side loads caused by debris and heavy wind pressure is absorbedby the materials (from which the silicone 24 and gaskets 51 are made),and supported laterally by the structural panels 43 and frame 1. Thisincreases the curtain wall's ability to resist lateral loads caused bywind and debris, and therefore, helps to satisfy the strict buildingcode requirements that exist in certain areas of the country.

[0034] The tiles 23 are preferably made of porcelain or other ceramicmaterial, and, because of the support provided by the frame 1, they canbe made relatively thin, i.e., a minimum of about ⅜ inch thick. Eachtile 23 is preferably cut and sized to cover the spaces formed by thehorizontal 3 and vertical 5 mullions, and therefore, has a maximumsurface area of about 9 square feet. The tiles 23 are also preferablyprovided with designs, colors and/or patterns that are aestheticallypleasing, and can be polished so that they are smooth to the touch.

[0035] The frame 1 is required to be properly supported and anchored tothe building on which the curtain wall is built, to help transfer thelateral loads from the walls to the building. For example, the frame 1can be mounted and supported by upper and lower building structures, 29and 30, respectively, which can be made of concrete, wood, metal orother building material. Along the top of the frame, as shown in FIG. 2,anchors 12 can be embedded or otherwise secured to the upper buildingstructure 29, such that connecting angles 15 can be mounted thereto. Theangles 15 can be extended from the upper building structure 29, and canhave flanges 14 on which fasteners 13, such as nuts and bolts, can beused to secure the horizontal mullions 3 to the building structure 29.Along the bottom of the frame 1, threaded anchors 16 can be embedded orotherwise secured directly to the lower building structure 30. Theanchors 16 are preferably extended upward to enable the lower horizontalmullions 3 to be secured to the building structure 30 using fastenersand nuts 16 as shown.

[0036] In FIG. 4, an alternative method of securing the horizontalmullions 3 to the upper building structure 29 is shown. In thisembodiment, threaded anchors 33 are used to directly secure the mullions3 to the building structure 29 with nuts. As discussed previously, theability to remove cover plate 11 from the tube portion 9 enables workersto access the interior of the mullion 3 to secure the nut on the anchor33. Any other method of anchoring the frame can be used. An exteriorgasket or sealant 27 is preferably provided between the mullions 3, andthe building structures 29 and 30, to seal the spaces therebetween. Abacker rod 31 can also be used to provide support for the spacings.

[0037] On the sides, as shown in FIG. 3, the frame 1 is preferablypositioned between two side building structures 61 and 63. An exteriorgasket or sealant 28 is preferably provided between the mullions 5, andthe building structures 61 and 63, to seal the spaces therebetween andprovide lateral support for the frame 1. Additional backer rods 31 canalso be used to provide support for the spacings.

[0038] Additional intermediate supports 55 and 57 can be provided tosecure the frame 1 to the building and transfer lateral loads from thecurtain walls, as shown in FIGS. 2 and 7, to the building. In thisrespect, frame 1 can be connected to an intermediate building support55, using an extended structure, such as an angle 57, anchored thereto,to provide bracing for the wall. The building support 55 can, forexample, be an intermediate floor, such as where the frame 1 extends toa height greater than the height of a single floor. The angle 57extending from the building support 55 is preferably connected to thevertical mullions 5 using through-bolts and slotted holes 65, as shownin FIG. 2.

[0039] The advantage of the curtain wall of the present invention isthat lateral design load capacities are increased to meet the stringentrequirements that exist in certain areas of the country where the threatof hurricane damage is high. For example, using the preferredconstruction described above, it is possible to satisfy the maximumdesign load capacity of 75 pounds per square foot imposed by the SouthFlorida Buidling Code for Dade County. The structure is also designed tomeet the wind loads per the latest version ASCE 7 using correspondingloads. These requirements were satisfied using a mullion spacing ofthree feet (for both horizontal and vertical members), a frame height ofup to 156 inches, and a bracing to transfer loads from the wall to anintermediate building support structure.

[0040] The invention has been discussed in terms of the preferredembodiments but should not be viewed as being limited thereby. Theinvention encompasses embodiments that are not specifically disclosedherein, but which are, nevertheless, covered by the claims.

What is claimed is:
 1. A curtain wall structure comprising: horizontalmullions spaced a predetermined distance apart from each other, andvertical mullions spaced a predetermined distance apart from each other,wherein said horizontal and vertical mullions are connected together toform a frame having a plurality of openings therein; support panels madeof a light weight material connected to said frame, said panelsextending across said openings; and tiles positioned on said frame, eachof said tiles being adapted to be positioned on the front side of saidpanels, wherein structural silicon is used to secure said tiles to saidpanels.
 2. The structure of claim 1, wherein each of said support panelshas an angled edge that extends around the perimeter thereof, saidangled edge being adapted to secure said panels to said frame andprovide rigidity to said panels.
 3. The structure of claim 1, whereinsaid support panels have a front surface that extends substantiallyalong the same plane as the front surface of said frame.
 4. Thestructure of claim 2, wherein fasteners are used to secure said anglededge of said panels to said horizontal and vertical mullions.
 5. Thestructure of claim 1, wherein a gasket is provided between the perimeterof said tiles and said frame to seal the space between said tiles andsaid frame.
 6. The structure of claim 1, wherein a top retainer isprovided along the upper edge of said frame to retain the tiles that arelocated on the upper part of said frame, said top retainer beingconnected to said upper edge of said frame along one of said horizontalmullions, and wherein a bottom retainer is provided along the lower edgeof said frame to retain the tiles that are located on the lower part ofsaid frame, said bottom retainer being connected to said lower edge ofsaid frame along another of said horizontal mullions.
 7. The structureof claim 1, wherein in the space between adjacent tiles gaskets orsealants are provided to form a seal between said tiles and said frame.8. The structure of claim 1, wherein each of said tiles has dimensionsin the horizontal and vertical directions that are greater than thedistances between the horizontal and vertical mullions, respectively,and wherein each of said support panels has dimensions in the horizonaland vertical directions that are substantially the same as the distancesbetween the horizontal and vertical mullions, respectively.
 9. Thestructure of claim 1, wherein said panels have a first predeterminedthickness, and said tiles have a second predetermined thickness, whereinsaid second predetermined thickness is greater than said firstpredetermined thickness.
 10. The structure of claim 9, wherein each ofsaid support panels has a horizontal edge portion extending around theperimeter that has a rearward dimension that is greater than said secondpredetermined thickness.
 11. The structure of claim 1, wherein saidtiles are made of porcelain or ceramic material.
 12. The structure ofclaim 10, wherein said tiles are no thinner than about three eighths ofan inch thick, and said support panels are made of aluminum that isabout one eighth inch thick.
 13. A curtain wall structure comprising:horizontal and vertical mullions spaced apart from each other, whereinsaid horizontal and vertical mullions are connected together to form aframe having a plurality of openings therein; support panels connectedto said frame, each of said panels having substantially the same sizeand shape as said openings, and having a perimeter edge extending normalto a front surface thereof, wherein said front surface of said panelsextends along a plane that is substantially the same as or in front ofthe front surface of said frame; and tiles connected to said frame andsaid panels, wherein structural silicon is used to secure said tiles tosaid panels.
 14. The structure of claim 13, wherein each of said panelsand tiles is larger in the horizontal and vertical dimensions than saidopenings, and wherein said panels are connected to said frame along theperimeter edge thereof.
 15. A method of forming a curtain wallcomprising: providing a frame having horizontal and vertical mullionsspaced apart from each other, said horizontal and vertical mullionsforming a plurality of openings therein; connecting a plurality ofsupport panels made of a light weight material onto said frame, saidpanels being positioned on said frame within said openings, wherein eachof said panels has substantially the same size and shape as saidopenings, and has a front surface that extends along a plane that issubstantially the same as, or in front of, the front surface of saidframe; and applying structural silicon to said panels and attachingtiles onto said panels using said structural silicon.